Osteoclastogenesis from embryonic stem cells

Osteoclasts are hematopoietic cells essential for bone resorption. To understand whole process ofosteoclastogenesis I have developed a culture system with a stromal cell linein which promotes differentiation of hematopoietic cell lineage，and terminal differentiation of osteoclasts from single embryonic stem cells.This culturedispended with any passage or manipulation enabled us to investigate temporal and spatiallocalization of osteoclast lineage in the colonies from undifferentiated ES cells. On 4日ofcultures,cell and endothelial cell lineages arose in the central site of colonies. Cellsexpressed tartrate-resistant acid phosphatase (TRAP - D1+ TRAP - D1) which is a specific marker ofosteoclast lineage first detected on day 8 and subsequently localize at the edge of colonies与maturate into TRAP a + multinucleated cells which have a potential of bone resorption. apotential of osteoclastogenesis of gene targeted ES cell lines in tal1, Gata-1Gata-1（-/-）和Fog(-/-) ES cells differentiate into osteoclastsnormally. No osteoclasts were detected in the culture of tal1 (-/-) ES cells. Gata-2(-/-) ES cells开发材料osteoclasts but the frequency reduced to one-tenth of normal ES cell lines. I alsodecided the ordered requirement for osteoclastogenesis as tal-1 --> Gata --> macrophagecolor -stimulating factor --> osteoclast differentiation factor. recently，I established a new文化系统for melanocyte development from ES cells. These systems areuseful tools for study of osteoclastogenesis，因为melanocytes是良好的内部控制的细胞dicision和文化条件。

Osteoclasts are hematopoietic cells essential for bone resorption. To understand whole process of osteoclastogenesis, I have developed a culture system with a stromal cell line, in which promotes differentiation of hematopoietic cell lineage, and terminal differentiation of osteoclasts from single embryonic stem (ES) cells.This culture dispended with any passage or manipulation enabled us to investigate temporal and spatial localization of osteoclast lineage in the colonies from undifferentiated ES cells. On 4th day of cultures, hematopoietic cell and endothelial cell lineages arose in the central site of colonies. Cells expressed tartrate-resistant acid phosphatase (TRAPィイD1+ィエD1) which is a specific marker of osteoclast lineage were first detected on day 8 and subsequently localize at the edge of colonies and maturate into TRAPィイD1+ィエD1 multinucleated cells which have a potential of bone resorption.A potential of osteoclastogenesis of gene targeted ES cell lines in tal-1, Gata-1, Gata-2 and Fog genes was examined. Gata-1(-/-) and Fog(-/-) ES cells differentiate into osteoclasts normally. No osteoclasts were detected in the culture of tal-1(-/-) ES cells. Gata-2(-/-) ES cells developed mature osteoclasts but the frequency reduced to one-tenth of normal ES cell lines. I also decided the ordered requirement for osteoclastogenesis as tal-1 --> Gata --> macrophage colony-stimulating factor --> osteoclast differentiation factor.Recently, I established a new culture system for melanocyte development from ES cells. These systems are useful tools for study of osteoclastogenesis, because melanocytes are good internal control of cell dicision and culture conditions.